


7/11 Free Slurpee Day

by Tipsyrainbow



Category: One Piece
Genre: Anal Fingering, Anal Sex, Blow Jobs, Consensual Underage Sex, M/M, Porn With Plot, Sibling Incest, Underage Sex
Language: English
Status: Completed
Published: 2019-09-04
Updated: 2019-09-04
Packaged: 2020-10-05 23:51:24
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 3,361
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20497427
Author URL: https://archiveofourown.org/users/Tipsyrainbow/pseuds/Tipsyrainbow
Summary: Luffy is seven, Ace is eleven, it's free slurpee day.or,It's Ace's birthday and Luffy has to distract Ace somehow.





	7/11 Free Slurpee Day

**Author's Note:**

  * For [Chokey Smokey (SpobSpucci)](https://archiveofourown.org/users/SpobSpucci/gifts).

“I told you to leave me alone already, Luffy.” Ace pouts, crossing his little arms over his chest. Luffy pulls at Ace’s hands and hangs onto him, despite the fact that Ace has explained his ‘personal bubble’ dozens of times. 

“But it’s your birthday! Birthdays are supposed to be fun!” Luffy smiles brightly, hoping that his happiness can somehow rub off on his big brother. Ace’s frown only deepens, and he turns away. How’s Luffy supposed to keep Ace happy and occupied in the treehouse while Sabo sets up? It’s the only thing Sabo asked him to do, so he has to do it good. But he can’t when Ace won’t listen!

“I’m going out.” Ace grumbles, heading towards the treehouse’s door with Luffy in tow. 

“No! You can’t!” Luffy jumps up, dragging Ace by the sleeve. “Come on, stay inside for just a little while?” 

Luffy had given him the biggest portion at breakfast, he’d deflected his questions on Sabo’s whereabouts even though Luffy is a terrible liar, he even let Ace sleep in this morning! Why was Ace being so difficult?

“Why do you want me to stay so bad, huh? I just wanna be alone!” Ace frowns, shaking Luffy off his arm. 

“Can you help me make a fire?” Luffy pleas. Maybe that will keep him busy.

“Can’t you do anything yourself?” Ace huffs, though he does pause for a moment before moving to pick up the spare firewood from the previous nights. Luffy sighs in relief. 

They sit in silence for a little while, and Luffy tries not to say anything because he knows Ace likes it to be quiet sometimes. He falls back on his butt and watches Ace arrange papers and little sticks in their makeshift wood stove built from scrap metal. Ace sits on his haunches facing away from Luffy, silent. Luffy can’t hold it for very long. He’s never been very good at this whole ‘quiet’ thing. 

“Ace, how come you’ve never celebrated your birthday?” He asks, digging his finger into his nose. Ace freezes. 

“It was never worth celebrating.” He says simply, but his tone is sharp. Luffy doesn’t catch it. 

“Really? I love celebrating my birthday. Makino always made me a cake, and this one time Shanks was there and he got me a- hey Ace are you alright?” Luffy blinks at Ace, whose mouth and nose begin to scrunch up in a grimace. 

“Fine. I’m fine.” Ace grinds out. “Now do me a favor and just get away from me.” He looks to the side with a little sniffle that Luffy doesn’t catch either. Ace’s hands ball into fists at his sides, and he slumps down in front of the stove completely. His back is to Luffy as he continues to work on the fire, wordlessly. 

Luffy’s small mouth hangs agape. What happened? A pit forms in his stomach and he feels like he’s done something horribly wrong, he just doesn’t know what. All he knows is he feels like crying because he upset Ace on such a special day, though he has no idea why. Luffy backs up and spins on his heel towards the door. He takes a step, then another, and pauses. 

He can’t let Ace down, not today. Today is supposed to be a good day. 

Luffy wheels himself around again and marches towards Ace’s hunched over back. Ace turns his head slightly from the pattering of Luffy’s feet. 

“Ace, you’re going to be happy today.” Luffy announces, cheeks puffed out. He crouches down and presses a gentle palm to his big brother’s shoulder. Ace shrinks from Luffy’s touch and coils further into himself like a spring ready to bounce. 

“I said leave me alone Luffy! Are you stupid or something? Just get out of here!” Ace barks, snapping around with bared teeth to face his young counterpart. Luffy shrivels back, his fingers shaking away from Ace’s shoulders with widened eyes. 

“I- I- I’m sorry, I didn’t mean to hurt Ace’s feelings, I’m sorry Ace.” Luffy sputters, backing away from Ace with wobbly legs. His little hands fly up to grip his straw hat for comfort. Ace’s eyes widen and he reaches a hand out. 

“No, Luffy, come here, I didn’t mean to…” He trails. Luffy stands still and pulls the hat further down his face, and Ace can see the little tears begin to slip over his cheeks. “Oh, Lu, no please don’t cry.” Ace’s voice gets soft and he motions with both hands for Luffy to come to him. Luffy takes small steps towards Ace and folds himself into his big brother’s arms, curling down with him on the wooden floor. 

“It’s okay Lu, shh.” Ace says with just the barest breath, smoothing his thumb over Luffy’s cheeks to wipe away the dirt and tears. Luffy looks up at Ace with round, wet eyes. 

“I just want Ace to be happy.” He says with a sniffle, leaning into the other’s palms. 

“I know Luffy, I know. You’re such a good little brother. Did you know that?” Ace smiles a bit, brushing Luffy’s hair with his fingers. His hair has got bits of mud caked in it, and dirt too, but it’s soft. Luffy brings his own hands up to rest over Ace’s own freckled cheeks.

“And Ace is the best big brother.” Luffy says, drawing his face down to press their lips together in a tender kiss, because that’s just what they do in these moments. Ace’s eyes slip shut, and his hand trails from Luffy’s wild locks to the nape of his neck. Luffy’s hands remain on Ace’s cheeks, his head tilting into his big brother’s lips. Ace pulls away after a moment, peppering a trail of butterfly kisses over Luffy’s soft, round cheeks and over his eyelids. 

“I love you, Lu. I don’t know where I would be without you.” Ace whispers against Luffy’s skin, his mouth drawing into a frown again. “You remind me I’m a person. Like I’ve got something to work for, to be here for. I’m so happy to have you, Lu.” He continues on, brushing his hands over Luffy’s cheeks, shoulders, arms, every bit of skin he can touch. Luffy gives a sunshine smile and giggles from the fluttering touches. 

“I love Ace too.” He says, bringing his own, smaller hands down to smooth over Ace’s neck and arms, resting on his thigh. “Ace is the best big brother, and that’s why I wanna celebrate so bad. Ace should be happy to be here, because he makes me happy.” 

“Oh, Lu...” Ace’s expression is pure adoration, his cheeks flushed like a strawberry. Luffy looks up at Ace, smiling still. His little hands wander over, and he squeezes at the juncture of Ace’s hip and thigh. 

“I wanna make Ace feel good, because I love him so much.” Luffy determines, nodding to himself. Ace sucks in a breath between his teeth. 

“Are you sure? You never do anything unless I ask first, what’s with the change of heart?” He says, the corners of his lips drawing up into a smug grin. 

“Ace gets a free one today! I don’t even want anything back, and you can do whatever you want, I can take it!” Luffy bounces up with a broad smile. 

“Anything?” Ace hums, standing as well. 

“Uhuh!” Luffy nods with vigor, happy to see Ace’s spirits rise. He’d do anything for Ace to be happy! Luffy grabs Ace by the hand and drags him to their straw beds, pushing him over into the makeshift mattress. Ace gives a light laugh, and Luffy does too, crawling over Ace to plant sloppy kisses all over his face and neck. 

“Stop it, stop it Lu!” Ace bats Luffy away with playful hands and grips him by the shoulders, rolling him over so that Ace hovers over Luffy. He smiles and leans down, catching Luffy’s lips in his own. He hums into his young brother’s mouth, running his tongue over Luffy’s lower lip and catching it with his teeth lightly. 

“Ow, that hurt.” Luffy rubs his mouth. 

“It’s supposed to, dummy.” Ace laughs, coming back down to kiss Luffy’s jawline lightly, alternating between his lips and tongue to graze any exposed skin. Luffy wiggles underneath Ace, pushing against him. 

“No fair, it’s supposed to be about you!” Luffy pouts. Without thinking, he draws a knee to push into Ace, though he only manages to grind it into his crotch by accident. Ace inhales sharply from the friction, already excited from the play.

“Got you.” Luffy grins, pushing Ace over until he’s on top again. Their lips connect once more, already heated, and Ace’s tongue finds Luffy’s in a wet mess of sudden, gripping desire. Luffy tugs at Ace’s shorts, fumbling with all the buttons and clawing at them to pull them down. Ace lifts his hips and shimmys the garment off, leaving nothing but his boxers between him and Luffy. Luffy grins, still not very confident in what he’s doing but knows Ace likes it when they do this. And it does feel good to make Ace feel good, and that’s what matters. 

“Remember what I said about the teeth, right Lu?” Ace says, and Luffy nods. 

“I’ll be careful, Ace.” He says, circling his little hands over Ace’s groin. He’s already hard from their antics, and Luffy can’t help the excitement that bubbles in his chest from making Ace feel so good. Luffy pulls down Ace’s boxers as much as he can before he dives down and takes the whole length into his throat. 

“Ah-h-hey slow down, Lu!” Ace grips the straw mat, his slim hips stuttering from the sudden wet heat. Luffy slows and going up and down Ace, his tongue flattened and cheeks hollowed. 

“Mmh, Lu.” Ace’s head rolls back, Luffy’s rhythmic movements drawing a certain tingling pressure into his groin. Luffy said he could do anything, right? Ace tests the waters, first rolling his hips against Luffy’s mouth. Luffy watches Ace from below with big round eyes, and he hunches down to get a better angle on him. Luffy’s hands trail and grip Ace’s backside for leverage. He swallows around Ace’s cock, and Ace groans in delight. 

“That’s so good Lu, you’re doing such a good job.” Ace grips a fistfull of Luffy’s hair, guiding him off slowly, then back on with force. Luffy chokes a little and Ace falters, but keeps his grip. 

“Yes, just like that, oh god, Lu.” Ace moans, thrusting just a little harder into his young brother’s sweet, stretching mouth. Ace can feel the sweat pooling on the back of his neck, and when he looks down to see Luffy’s reddened cheeks and wide eyes staring back, he has to bite his lip to keep from being too loud. 

All too soon, Luffy’s small mouth draws away. 

“Nooo…” Ace groans, falling back into the straw mat. He looks up again when he feels something new, and his breath catches. 

“Does this feel good, Ace?” Luffy asks, his voice small. His voice is hoarse and his cheeks are all red, a mess of saliva and sweat. Luffy’s tongue swirls over the tip of Ace’s cock, lazy trails of saliva and peppering kisses. He presses his cheek against the length with a hazy smile. 

“I love Ace so much.” Luffy hums, rubbing against Ace. Ace can’t handle the light licks and kisses anymore. Something had been boiling in his belly this whole time, each little caress like a match to a fire, and just seeing Luffy like this sets Ace off. He wants something more and he doesn’t even know what. All he knows is his cock is twitching and tight to the point of bursting, and he needs more. He’s heard of sex in theory from those books, but he doesn’t even know if that will work because Luffy is a boy.

“Luffy we’re going to do something else.” Ace growls, sitting up so fast he almost knocks Luffy over. 

“Is it not good?” Luffy blinks. 

“No, you’re doing really good. Really, really good.” Ace grinds out, crawling over Luffy, hovering his fragile little body. “I’m just taking over.” He says, gripping Luffy’s jaw and catching him in a kiss. 

“Mmph!” Luffy’s eyes widen at the sudden roughness. This wasn’t Ace at all, unless they were fighting. Maybe Ace thought that’s what they were doing. Ace nips at Luffy’s skin all over, shoving his clothes out of the way to drink up more skin. Luffy’s rubbery skin is soft and glistening with sweat, and Ace just finds himself trailing down further and further, ripping Luffy’s own shorts away. His hands find Luffy’s own little bobbing cock, and Luffy cries out from the touch. 

“Ah, Ace!” He whimpers. Ace goes down further, boosting Luffy’s ass up and legs out with one hand and encircling the ring of muscle with the other. He read about lubrication. They don’t have anything like that, so Ace sticks his fingers in his mouth, wets them with saliva, and draws them out. He brings them back to their goal and pushes inside. 

“Ace-! What are you doing-!” Luffy gasps, feeling something wet and hot crawling inside him. 

“Thank god you’re made of rubber.” Ace pants out, scissoring Luffy open. “I’m putting it inside you. It’s called sex.” He says, spitting more saliva into his fingers. 

“W-what? You’re putting your thing. In my… my…” 

“In your ass, Luffy.” Ace rolls his eyes, but with a grin. He can’t help but feel giddy, just imagining how Luffy will feel around him. He sticks a third finger in. 

“I’m not s-sure how I like it.” Luffy mewls out, his head back, mouth agape. Ace curves his fingers a little deeper. He’s not sure how he’s supposed to do this.

“A-ah, Ace!” Luffy wails when Ace hits something deep inside him, and he grinds into Ace’s fingers. That’s enough. Ace nearly rips his fingers out and draws himself over Luffy, clumsy with anticipation. He wets his cock with more saliva and presses in, the head of his cock slipping inside so easily. Thank god he’s rubber.

“I’m. I’m inside you.” Ace says, still, breathless. 

“I-it feels weird.” Luffy moans out, throwing an arm over his face. 

“I’m having sex with you, Luffy.” Ace says, more so because he can’t believe what’s happening himself, it feels so good. Why did the bandits never tell them they could do this? 

“Luffy…” Ace grinds out between panting breaths. “I’m going to move now, okay?” He pushes in deeper, and it’s not much, but Luffy’s never had anything inside him before. He writhes against every inch, twisting and contorting his body around Ace between discomfort and ecstasy. His mouth hangs wide open in hazy, panting pleasure, and his own little hands trail down to stroke himself while Ace slowly, slowly thrusts into him. Ace grips at Luffy’s thighs, holding them for leverage. He groans out when he sees Luffy touching himself, to think, he could do this to his younger brother. 

“A-Ace feels so good…” Luffy moans out, his head knocking to the side like a ragdoll. 

“You feel… incredible, Lu…” Ace says, gaining better control of his hips to thrust in and out with more accuracy. He searches for that spot that made Luffy feel so good before, but he can barely think from the pure, boiling bliss running through his veins. 

Eventually, Ace’s hips find a rolling rhythm that seems to pierce Luffy right where he likes it, because with each thrust he’s all but screaming out Ace’s name, or at least some broken version of it. 

“Lu, Lu, I’m so close.” Ace babbles out, breathless. He smooths his hands over Luffy’s bare, glistening skin. 

“Me too, Ace.” Luffy nods with a breathy moan, squeezing at his own erection. 

Ace’s movements start getting frantic, and he runs his hands over Luffy’s thighs. 

“Let me finish you off.” Ace says, his voice low. He spits more saliva into his free hand and starts stroking Luffy roughly with the intent of dragging him to orgasm. 

“Ah-Ace-! Too much! Too fast!” Luffy cries out, tossing his head back and forth on the straw mat. That only makes Ace work harder, stroking and thrusting at once. His muscles burn and his movements are frantic, but watching Luffy writhe and that burning sensation deep in his belly keep him going. It boils and builds, and he can’t take it anymore. 

“Come on Luffy, come on!” He growls, and Luffy throws his head back. 

“A-Ace-! I’m-!” He cries, his muscles contracting with force as he finishes, screwing his eyes shut as the tremors take over. He tightens around Ace’s cock, and Ace doesn’t expect it, nearly doubling over from the sensations all over his body. With two free hands he focuses on thrusting into Luffy, so, so close. The fire in his belly builds and burns, and he grinds deep into Luffy, crying out with his own white hot release. 

It’s there, and then it’s gone in an instant, replaced with the happy aftershocks of pleasure and lazy slowness. Ace folds over Luffy to catch his breath for a moment before he is able to pull out, barely enough strength in his body to fall down next to him on the mat. 

“Was that good for Ace too?” Luffy looks over with a slow smile, his hair disheveled. His hat must have fallen off at some point. Ace nods with panting breath, his release much fresher than Luffy’s.

“I love you, Lu.” Ace says. Luffy cuddles up to Ace’s side and rests his head on his chest. 

“I love Ace too.” He says. 

They don’t have much time to remiss in the afterglow before a certain knock sounds at the door. As if he had all the energy in the world, Luffy jumps up and quickly grabs his shorts. The color drains from Ace’s face. Sabo. Shit. He didn’t know that Ace was still sometimes doing that with Luffy! Ace grabs his own shorts and yanks them up, straightening out his appearance. They probably look like a mess. 

The door opens. Oh god. 

“Hey guys!” Sabo walks right inside, and Luffy gives him the widest smile. 

“Sabo! Mission accomplished, sir!” Luffy salutes, grinning. 

“Great!” Sabo pauses, and wrinkles his nose. “Man, we have got to open some windows in here. It smells so musty.” 

“Yeah, right? That’s so weird.” Ace gives a nervous laugh, and Sabo gives him an incredulous look. 

“Anyways. Ace, Luffy? Come with me.” Sabo shakes his head and motions for Ace to follow. Ace feels like dying inside, so he does what Sabo asks. Luffy follows suit, smiling brightly. 

Sabo leads down the treehouse and into another storage area. It’s cold from the snow, but manageable. He turns on a light, and the whole room illuminates. Ace can’t believe his eyes. 

“Tada!” Luffy jumps up on his toes, straining to see Ace’s reaction. Ace’s mouths hangs open. 

The room, previously cluttered, has been cleaned out and in the center of the room is a table with three chairs. Presents line the floor, there’s balloons, and even a cake. 

“This is… for me?” Ace turns and looks at his brothers. “Did you guys buy me a cake? That must have been a fortune…” He says softly. His lip quivers, and before he can say anything else, Sabo and Luffy both gather him into a hug. 

“I’ve been setting this up all morning, I told Luffy to keep you busy.” Sabo says, drawing away. He turns to Luffy. “I can’t believe you managed it! Normally he storms off by now. Hey, you have something on your cheek…” 

Ace snaps his gaze over to Luffy, who indeed, has cum right on his face. Ace quickly wipes it off with the back of his hand. He lets out a glowy nervous laugh. 

“Anyways, thank you guys. I really do have the best brothers in the world.” He says. 

“Time for cake!!” Luffy jumps up, and the others laugh. All is right in the world. 

Luffy slips his hand into Ace’s under the table, and he can’t help but find himself blushing.

**Author's Note:**

> you'll never hear 7/11 free slurpee day the same again. I don't.
> 
> but thank you so much for reading, feedback is very much appreciated!!


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